lkml.org 
[lkml]   [2008]   [May]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] drivers/net: remove network drivers' last few uses of IRQF_SAMPLE_RANDOM
Brandeburg, Jesse wrote:
> we've been hearing rumblings of big customers wanting (maybe requiring)
> wired network drivers from Intel to advertise this flag. Jeff have you
> heard of such?

I do indeed hear requests all the time, from people who want to make
their boxes externally exploitable. :)


> I think the argument is that a headless system (no keyboard/mouse, no
> soundcard, probably no video) with a libata based driver and a network
> driver without IRQF_SAMPLE_RANDOM has *no* sources of entropy. In this
> case the argument is very strong for at least *some* source of entropy
> from interrupts so that randomness can get some external input. Just
> try rebuilding a kernel RPM over an ssh session and you'll see what I
> mean.

There are entropy sources on a headless box, even one without audio and
video, that are more secure than adding IRQF_SAMPLE_RANDOM to network
drivers.

EGD demonstrates this, for example: http://egd.sourceforge.net/ It
looks at snmp, w, last, uptime, iostats, vmstats, etc.

And there are plenty of untapped entropy sources even so, such as
reading temperature sensors, fan speed sensors on variable-speed fans, etc.

Heck, "smartctl -d ata -a /dev/FOO" produces output that could be hashed
and added as entropy.

I'm interested to hear peoples' opinion of Chris P's patch, but
definitely do not want to go in the other direction and start adding
IRQF_SAMPLE_RANDOM, thus moving randomness in the direction of being
externally exploitable.

Jeff





\
 
 \ /
  Last update: 2008-05-15 20:07    [W:0.162 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site